“…This stabilizes TOP1cc and prevents further religation of the broken DNA. When replication and transcription machineries encounter the trapped TOP1cc, DNA damage is generated, triggering cell death. , To date, four well-known camptothecin TOP1 inhibitors (Figure 2S, Supporting Information) have been approved for clinical treatment of cancers, including irinotecan ( 2 ) and topotecan ( 3 ), approved by the FDA, − 10-hydroxycamptothecin ( 4 , HCPT, in China), and belotecan ( 5 , in South Korea). ,, Therefore, TOP1 is a validated target for the discovery of antitumor agents. ,− …”